How do the students change and feel about Stargirl in Chapter 6?

In Chapter Six, Hillari approaches Stargirl in the lunchroom and tells her not to sing Happy Birthday to her the next day (on Hillari's birthday), and Stargirl says she won't. The next day the tension in the lunchroom is obvious as everyone waits to see what happens. As Stargirl stands up and begins strolling and strumming, she walks over to Leo and sings Happy Birthday to Hillari (instead of directly to Hillari). At the end of the song the students applaud.... they appreciate her ingenuity.